Overexpression of <i>HYOU1</i> is associated with cisplatin resistance and may depend on m⁶A modification in patients with cervical cancer

Cervical cancer (CC) is the fourth leading cause of cancer-associated mortalities among women worldwide. The chemotherapeutical platinum-based agent cisplatin (DDP) is the standard therapy for locally advanced or recurrent CC; however, platinum resistance limits its clinical benefit. Therefore, the present study aimed to identify key genes associated with DDP resistance in patients with CC and investigate the underlying molecular mechanisms. Firstly, using the CRISPR-Cas9 dataset of CC cells derived from DepMap portal, 699 genes associated with CC cell survival were identified. Subsequently, using the gene expression profiles of normal and CC samples with a response status to DDP, derived from The Cancer Genome Atlas (TCGA), hypoxia upregulated 1 (<i>HYOU1</i>) was further identified as significantly upregulated in CC samples and patients that did not respond to DDP (non-responders) when compared with healthy controls and patients that did respond to DDP (responders), respectively, using unpaired student's t-tests. Additionally, the log-rank test revealed that the high expression of <i>HYOU1</i> was significantly associated with the poor survival of patients receiving DDP. The association between the high <i>HYOU1</i> expression levels and the poor survival of patients receiving DDP was validated in the remaining TCGA dataset of patients with CC. <i>HYOU1</i> expression levels were positively associated with the half-maximal inhibitory concentration value of DDP in CC cells using data derived from the Genomics of Drug Sensitivity in Cancer database. <i>In vitro</i>, western blotting experiments revealed high HYOU1 protein expression levels in DDP-resistant HeLa cells compared with their parental HeLa cells. Furthermore, the knockdown of <i>HYOU1</i> resulted in an increased sensitivity of HeLa cells to DDP. Finally, using the sequence-based RNA adenosine methylation site predictor program, it was found that N⁶-methyladenosine (m⁶A) was highly enriched in HYOU1. The expression levels of the m⁶A reader, <i>EIF3A</i>, was positively correlated with the expression levels of <i>HYOU1</i> and was upregulated in the non-response group compared with the response group in a dataset from TCGA database. Additionally, <i>EIF3A</i> had the highest probability of binding to the m⁶A motifs of <i>HYOU1</i> compared with other genes. In GSE56363 obtained from the Gene Expression Omnibus, the non-responders had significantly increased expression levels of <i>EIF3A</i> compared with the responders. In conclusion, high expression levels of <i>HYOU1</i>, which may be regulated by <i>EIF3A</i> due to m⁶A modifications, was associated with DDP resistance in patients with CC and could potentially be used as an indicator of DDP treatment resistance.